We recently identified the immediate progenitors of the two major cDC subsets and showed how the interaction between two key transcription factors, IRF8 and BATF3 regulates lineage restriction and commitment in cDCs. We now aim at characterizing pDC precursors and understanding the transcriptional requirements necessary to define lineage determination. pDCs are a major source of Type I IFNs, which is required for innate response upon viral infections. In addition, pDCs can participate in the priming of T cells and were suggested to contribute to the pathogenesis of autoimmune diseases. However, since their discovery in human Lymph nodes in 1958, the precise contribution of pDCs to immune responses is still poorly understood. Identifying the precursors and defining the transcriptional landscape required for lineage determination as well as lineage identity is essential to dissect their function at steady state as well as during immunity.